Composite products (e.g., ceramic reinforced metals and metal reinforced ceramics) comprising a metallic constituent and a second component, such as a strengthening or reinforcing phase (e.g., ceramic particulates, whiskers, fibers or the like) show great promise for a variety of applications. However, in some cases a metallic constituent., or at least one metallic component of the metallic constituent, in a composite body may prevent the composite body from being used in some industrial applications. For example, if a composite body contained an aluminum component as, or in, the metallic constituent, and also contained a ceramic phase or component, the aluminum component, if present in substantial amounts, could prohibit the composite body from being utilized in, for example, certain high temperature applications, certain corrosive environments, certain erosive environments, etc. Thus, in some cases, it may be desirable to remove at least a portion, or substantially all, of a particular component in the metallic constituent or the metallic constituent itself from the composite body.
Various methods for removing a metallic constituent from a composite body are known in the art. Specifically, the general knowledge that a metallic constituent can be leached from a composite body exists. Moreover, the general knowledge that the simultaneous application of temperature and some type of mechanically applied pressure to remove a metallic constituent from a composite body also exists. However, these methods have drawbacks associated with them. For example, the simultaneous application of temperature and pressure could have a deleterious effect upon the microstructure of the composite body. Moreover, the shape of the composite body could be adversely affected if a large amount of pressure was applied. Likewise, subjecting a composite body to a leaching step could also have deleterious effects upon the microstructure (or macrostructure) of the composite body. Still further, these processes may not reliably remove substantial portions of a metallic constituent unless long amounts of time and/or relatively high temperatures are provided for metallic constituent removal. Moreover, such methods may not be capable of selectively removing one or more metallic components within a metallic constituent.
Accordingly, there has been a long felt need for a simple and reliable process to remove from certain composite bodies some or all of a metallic component of a metallic constituent, as well as removing some or all of the metallic constituent itself, said process not relying upon the use of applied pressure or vacuum (whether externally applied or internally created). The present invention satisfies these and other needs by providing a technique for the removal of at least a portion, or substantially all, of a metallic constituent from a composite body, without. the requirement for the application of pressure, etc. Moreover, the present invention provides a technique for the selected removal of at least one metallic component of a metallic constituent and/or selected areas of removal of at least one metallic component of a metallic constituent from the composite body.